Tundra climates are characterized by sub-freezing mean annual temperatures, large annual temperature ranges, and moderately low precipitation. The tundra climate region occurs between 60° and 75° of latitude, mostly along the Arctic coast of North America and Eurasia and on the coastal margins of Greenland. In areas dominated by the tundra climate type, winters are long and cold, especially in the region north of the Arctic Circle where, for at least one day in the year, the Sun does not rise. Winter precipitation generally consists of dry snow, with seasonal totals less than in the summer when cyclonic storms that develop along the boundary between the open ocean and sea ice yield rainfall. Typical annual totals are less than 350 mm (13.78 in), but higher totals are possible in upland areas. In contrast, summers are generally mild, with maximums from 15 to 18 °C (59°F to 64°F), although the average temperature of the warmest month is less than 10°C (50 °F). Days are long, but they are often cloudy.

The Köppen Climate Classification subtype for this climate is "ET". (Tundra Climate).

The average temperature for the year in Sankt Jakob is 37.4°F (3°C). The warmest month, on average, is July with an average temperature of 55.8°F (13.2°C). The coolest month on average is January, with an average temperature of 18.5°F (-7.5°C).

The highest recorded temperature in Sankt Jakob is 89.8°F (32.1°C), which was recorded in July. The lowest recorded temperature in Sankt Jakob is -21.6°F (-29.8°C), which was recorded in January.

The average amount of precipitation for the year in Sankt Jakob is 36.4" (924.6 mm). The month with the most precipitation on average is July with 5.1" (129.5 mm) of precipitation. The month with the least precipitation on average is February with an average of 1.3" (33 mm). There are an average of 71.3 days of precipitation, with the most precipitation occurring in July with 9.9 days and the least precipitation occurring in December with 4.2 days.

In Sankt Jakob, there's an average of 140.3" of snow (0 cm). The month with the most snow is February, with 25.0" of snow (63.5 cm).